Cementation and hardening of iron and steel articles.



G. STOLLE & A. HOCKS.

CEMENTATION AND HARDENING OF IRON AND STEEL ARTICLES. I

APPLIQATION FILED JULY 31. 1915.

1., 178,551. Patented Apr. 11,1916.

CEMENTATION Am) nnnnnnme or IRON ,ANDSTEEL ARTIIECLES,

To all whom it may oonoerm ALFRED HOOKS, subjects of the German'Emperor, and residing at Kiel, Germany,- have invented certain new and useful Improvements in ,Cem'entation and lrlardening of Iron and Steel Articles; of; fol-&l

.' lowing'isa specification.

This invention relates to amethod of effectively employing the surface treatment of iron and steel articles for the purpose of improving their quality and more par- 7 ticularly to the cementation or hardening of iron.

As is well known the cementation or hardening of iron is usually efi'ected by casehardening, viz. by embedding the article in the case-hardening material and heating the Whole to incandescence in a special furnace.

The packing of the article in the case-har-' dening material and the'subsequentheating to incandescence and cooling of the whole mass of iron takes up much time. In many cases also owing to the form and'weight of a particular article it is diflicult or impossible to insert it into the furnace.

The object of the invention is to overcome these drawbacks and to rovide a hardening process in which pac 'ng of the articlein material and heating the whole piece'is avoided; 1 a

A further object of the-invention is to simultaneously efi'ect'in the useof the process improvements in the quality of the metal other than hardening and in fact such other improvements in quality may-in some cases form the sole object of the process.

The invention consists of a method for locally heating the article and simultaneously spraying suitable material onto the heating region.

Our invention will be best understood by reference to the following description in connection with'the accompanying illustration of one specific embodiment thereof.

The drawing shows in vertical section suitable apparatus by means of which our invention may be effectively carried out,

parts of such-apparatus being shown in side p Specification of Letters Patent. j Application filedJ'ifly 31, 1915. Serial No. 43,031;

atented ain, 1916.

- bottom of which is connected means of Be it known that we, GEoRo S'roLLn and 7 y "NrrED sTATES-P O i GEORG STOLLE AND ALFRED HOCK S, OF GERMANY.

a conduit 0, with agasblow-pipe do The vgas-blowpipe consistslof two tubes e and 1 one of .w-hlch, surrounds the other. and the end of theficonduit a; The outer tube e is in communication with aconduit e for com pressed air or; gas while the tube f which 'surrou'nds the end of .the conduit 0 and is itself surrounded by the tube e, co1nmunicates with a conduit 1" for theheating gas.

The conduits e and F as well a's'the conduit v o are provided withsuitable'cocks k. The

vacuum produced by the stream-"of fluid or by the flame flowing from thet'ubes e and f of the gas-blow pipe I? c auses' the material m to be-sucked ofi' from -the conduit 0 and face of the piece a, For the fromobstru ction a conduit 9 for compressed air or gas 1s connected to the reservoir 6 near its bottom, said conduit being a1so pro-- vided with a suitable cock 7c.

.In carrying the invention into efiect, for

example in hardening iron, the cooks is of .the conduits e and f are opened and the y I stream of fluid flowing from the gas-blow pipe 01 is lighted. The piece a is moved past the flame'of the gas-blow pipe d by any suit able means (not shown) and heated to red heat over that portion of the surface which" it is desired to harden. I .v

After the piece a has attained the at slred color over that portion of the" surface which it is desired to harden the cock is. of

conduit 0 is opened and pulver'ulent carbon in any suitable form, such for example as pure carbon, binary, or ternary, or higher an or gas current and simultaneously sprayed on to the heated region. The, cock k of the compressed'air conduit 9 is opened at the same time as cock is of conduit c.

Once the desired degree of hardness is'obtained, all of the cooks lo are closed. .The carbon may also be carried through the source of the heat and sprayedon to the ar- 9 5 i alloy of nickel, chromium, vanadium, tung sten molybdenum and the like, is sucked off from the reservoir 6 by the compressed ticle by a'current of compressed; air or gas I capable of regulation. Furthermore a gas rmxture may be conducted under. ressure to be projected on to'the heated'sur cc of the iron hardened. By a suitable regulation of pressure and vof gas or air supply or both,

the resulting imperfect combustion of the gas may be made to produce a deposit of carbon.

When it is desired merely to improve the quality, for example of an article made of iron containing already in itself a sufiiciently high percentage of carbon, then the material sprayed on to the metal may consist of metals or metallic alloys having a low percentage of carbon or free from carbon. Such material as boron and silicon or their compounds may also be used.

The source of heat used for heating the portion of the surface to be treated may be a flame fed with suitable'combustible material either solid or fluid or in the form of gas or vapor.

' What we claim is 1. The method of improving the quality of iron and steel articles by surface treat ment which consists in the application of means for locally heating the article and simultaneously spraying suitable material onto the heated region by means of said heating means.

2. The method of cementation or hardening for an article constructed of iron or steel which consists in subjecting a portion of the surface of said article to a heating medium, and in locally applying suitable hardening material by means of said heating medium.

3. The method of improving the quality of iron and steel articles by surface treatment, which consists in locally heating the article with a heating flame and simultaneously spraying suitable material on to the heated region, by means of said flame.

4. The method of cementation or hardening for. an article constructed of iron or steel which consists in subjecting the iron or steel to the heating etlects of a heating medium, and in the local application of hardening material to the heated iron or steel by means of said heating medium.

5. The method of surface treatment of iron and steel articles already containing a sufficiently high percentage of carbon which consists in the application of means for locally heating the article and simultaneously spraying on to the heated region by said heating means metals, metallic-alloys or other suitable material.

In testimony whereof we aflix our signatures in presence of two witnesses.

' GEORG STOLLE. ALFRED HUCKS.

Witnesses:

JULIUs Rorxn, WILHELM KRfITZFELDT 

